EVOLUTION

Evolution• The process of how organisms

acquire adaptations over time

Adaptation• An inherited trait that helps an

organism survive• Includes body structures that help

an organism feed, move around and protect itself

Geologic Timeline

4.6 billion – 38,000 million years ago (mya)

• The Earth was extremely hostile to life as we know it

3800 to 2500 mya1. Oldest sedimentary rocks2. First life appears (single celled organisms without nuclei).3. Oldest fossils4. Single celled organisms begin to perform photosynthesis5. Primitive eukaryotes (singlecelled organisms with nuclei) appear

2500 to 1600 mya • Cyanobacteria (bacteria that

perform photosynthesis) begin to add oxygen to the atmosphere.

1600 to 900 mya • The first land fungi

appear.

900 to 650 mya • Soft bodied organisms

appear.

544 to 500 mya1. Animals begin to be capable of vision.2. Vertebrates (animals with backbones) appear.

500 to 440 mya• First land plants appear.

440 to 410 mya• Fish and vascular plants

appear

410 to 360 mya1. Land is colonized by plants and animals2. Insects, sharks and amphibians appear

360 to 325 mya• Reptiles appear.

245 to 208 mya1. The supercontinent Pangea breaks up.2. Dinosaurs, crocodiles, and turtles appear.

146 to 65 mya1. Extinction of the dinosaurs.2. Flowering plants, lizards, snakes, andsocial insects appear.

65 to 54 mya•Mammals appear.

54 to 37 mya1. Grass appears.2. Primates, camels, cats, dogs, horses and rodents appear.

5 to 1.8 mya• Ape-like ancestors of

humans appear

1.8 million to 11,000 years ago

1. Ancestors of man first walk upright (Homo erectus)2. Homo sapiens appear

11,000 years ago to today1.Last major ice age ends.2.Modern man migrates to

the Americas